/Engine/Plugins/Runtime/RigVM/Source/RigVMDeveloper/Public/RigVMModel/Nodes/RigVMTemplateNode.h
Returns a default value for pin if it is known
[FString](API\Runtime\Core\Containers\FString) GetInitialDefaultValueForPin ( const [FName](API\Runtime\Core\UObject\FName) & InRootPinName, const [TArray](API\Runtime\Core\Containers\TArray)< int32 > & InPermutationIndices ) const